{"paper":{"title":"Kinematic distributions of the $\\eta_c$ photoproduction in $ep$ collisions within the nonrelativistic QCD framework","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"hep-ph","authors_text":"Army Medical University, Astrophysics, Center of Excellence in High Energy Physics, China), Chongqing, College of Basic Medical Sciences, Economics, Guiyang, Guizhou University of Finance, Hong-Fei Zhang (College of Big Data Statistics, Nakhon Ratchasima, Southwest University, Suranaree University of Technology, Technology, Thailand), Wen-Long Sang (School of Physical Science, Yu Feng (Department of Physics, Yu-Peng Yan (School of Physics","submitted_at":"2019-02-25T01:59:53Z","abstract_excerpt":"We study the $\\eta_c$ photoproduction in $ep$ collisions in this paper. The short-distance coefficients for $c\\bar{c}(^1S_0^{[1]})$, $c\\bar{c}(^1S_0^{[8]})$, $c\\bar{c}(^3S_1^{[8]})$, and $c\\bar{c}(^1P_1^{[8]})$ photoproductions are evaluated at leading order in $\\alpha_s$ expansion, where the color-singlet contribution is achieved for the first time. We have carefully analyzed different kinematic distributions of the cross sections and found that the color-singlet contribution is considerably suppressed comparing with the color-octet parts. This feature renders the $\\eta_c$ photoproduction pro"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1902.09056","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}